Generally, hydraulic excavators, typical of construction machines, are largely constituted by an automotive vehicular lower structure, an upper revolving structure swingably mounted on the vehicular lower structure through a swing mechanism, a working mechanism built of boom, arm, bucket members liftably provided on a front side of the upper revolving structure and hydraulic cylinders for operating these members.
The upper revolving structure is largely constituted by a revolving frame, an operator's seat provided on the revolving frame, an engine mounted in a rear side of the revolving frame to drive a hydraulic pump, a plural number of control valves mounted on the revolving frame to supply and discharge pressure oil from the hydraulic pump to and from a vehicle drive motor of the vehicular lower structure, hydraulic cylinders of the working mechanism and swing motor of the swing mechanism, and control levers located closely at the right and left sides of the operator's seat to control the control valves for operating the working mechanism and the swing mechanism.
Further, certain hydraulic excavators are provided with a pattern selector valve for switching a pattern of operations of control valves which are hydraulically connected with right and left control levers (e.g., as disclosed in Patent Literatures 1 and 2 below). A pattern selector valve is provided, for example, for switching control levers of a leased hydraulic excavator to an operating pattern which is familiar to or preferred by an operator. Usually, the pattern selector valve is provided in the course of pilot pressure ducts which are connected between a group of control valves and the control levers.
Patent Literature 1: Japanese Utility Model Laid-Open No. S63-135004
Patent Literature 2: Japanese Patent Laid-Open No. 2001-330004
In the case of the prior art hydraulic excavators, a box-like selector valve mount bracket is provided on an engine front cover which covers a front side of an engine, and a pattern selector valve is mounted on the selector valve mount bracket within an engine room in such a way that a switch lever of a manual switch member is located on the rear side. The switch lever of the pattern selector valve can be manually operated after opening a bonnet which covers a rear side of the engine (e.g., as disclosed in Patent Literature 3 below).
Patent Literature 3: Japanese Patent Laid-Open No. 2001-40702
Further, in certain hydraulic excavators, a pattern selector valve is located within a right cover on the right side of an operator's seat. In this case, a switch lever of the pattern selector valve can be manually operated after opening the right cover. Further, in certain hydraulic excavators, an indicator device is provided within a view field of an operator who is seated on an operator's seat, showing a guide to control lever actions in relation with operations of a working mechanism and a swing mechanism, along with a currently selected operating pattern (e.g., as disclosed in Patent Literature 4 below).
Patent Literature 4: Japanese Patent Laid-Open No. 2003-56011
Further, in the case of another hydraulic excavator, a pattern selector valve is accommodated in a space which is formed by stepping up part of a floor panel at the foot and on the left side of an operator who is seated on an operator's seat. In this case, a switch lever of the pattern selector valve can be manually operated by removing a rubber cover which cover the pattern selector valve (e.g., as disclosed in Patent Literature 5 below).
Patent Literature 5: Japanese Patent Laid-Open No. 2002-227249
In the case of the hydraulic excavator according to Patent Literature 3 mentioned above, an operator has to get down from the operator's seat and walk to the rear side of the hydraulic excavator and open the bonnet to check out the position of the switch lever of the pattern selector valve or to operate the switch lever of the selector valve position. This is troublesome and time-consuming. Besides, it takes time in mounting a box-like selector valve mount bracket in the engine front cover, in addition to a higher production cost.
Further, in the case of the hydraulic excavator according to Patent Literature 4 mentioned above, it is possible for an operator, who is seated on an operator's seat, to check out the position of a switch lever of a pattern selector valve on a display. However, in order to manually change over the switch lever of the pattern selector valve, the operator has to get down from the operator's seat and walk halfway around to reach the right side of the hydraulic excavator and open the right cover. The operation of the switch lever requires troublesome and time-consuming efforts.
Furthermore, in the case of the hydraulic excavator according to Patent Literature 5 mentioned above, the pattern selector valve is mounted on an uplifted floor panel portion on the left side of an entrance way to the operator's seat, posing itself as an obstacle to an operator who is getting on or getting off the machine.